crook



(Nu Model.) 2 Sheets-Sheet 1.

0. M. GROOK.

. ELECTRIC CLOCK. 7 No. 574,669. Patented Jan. 5, 1897.

minefiggeis I @W 672 07", 6

- UNITED STATES PATENT OFFICE.

CHARLES M. CROOK, OF CHICAGO, ILLINOIS, ASSIGNOR TO CHARLES S. BURTON,TRUSTEE, OF SAME PLACE.

ELECTRIC CLOCK.

SPECIFICATION forming part of Letters Patent No. 574,669, dated January5, 1897.

Application filed December 12,1895. Serial No. 571,866. (No modeLl T0LLZZ whont it NMLZ/ conccrlo:

Be it known that 1, CHARLES M. CRooK, a citizen of the United States,residing at Chicago, county of Cook, and State of Illinois, haveinvented certain new and useful Improvementsin Electric Clocks, whichare fully set forth in the following specification, reference being hadto the accompanying drawings, forming a part thereof.

This invention relates to clocks which are operated by springs orweights wound at intervals by the force of an electric current operatingthrough an eleetromagnet upon a winding device, and which aresynchronized periodically by setting devices which are operated by theforce of another electromagnet, the circuit through which is closed bythe clock-movement at the predeteri'nined time for synchronizing.

In the drawings, Figure 1 is a front elevalion. Fig. 2 is a sideelevation of the clocktrain, including the winding and synchroniz-. ingparts. Fig. is a detail section at the line 3 L3 011 Fig. 2, showing thewinding devices and the electromagnet which operates the same. Fig. atis a detail section at the line-1il on Fig. 2. Fig. 5 is a detailsection at the line 5 5 011 Fig. 4. Fig. 0 is a detail elevation showingthe minute and seconds hands and the synchronizing device in a positionoccupied at the instant of synchronizing M is the frame.

N is the winding-magnet; I, the synchronizing-magnet both being mountedfixedly with respect to the frame.

The principal train-that is to say, the train from the mainsprin g tothe escapeme'ntcomprises the wheels within the case on the shafts a, b,and c, the shaft ct being that about which the mainspring is coiled,having the main gear-wheel A; the shaft 1) having the pinion B, meshingwith and driven by the gear A, and having also the gear B the shaft 0having the pinion C, which meshes with and is driven by the gear I 3,and having also the escape-wheel C.

d is the escapement-stalf, carrying the escape-dog D and thependulum-lever D.

I have shown the mainspring E held at the outer end by the post M andadapted to be wound from the inner end, being therefore secured at theinner end to the winding drum or sleeve E, Which has the ratchet-wheel Eadjacent to the gear-wheel A and adapted to communicate motion theretothrough the ratchet-dog A in a familiar manner.

My invention does not exclude other familiar forms of communicatingpower from the spring to the main wheel and thence to the train; but theobjection which sometimes exists to this formthat the train is deprivedof driving-im pulse during the period of winding-is obviated in mystructure by the fact that the winding is instantaneous, taking place inless time than required for the passage of one tooth of theescape-wheel-that is, in less than one tick of the clock.

On the sleeve E and rigid with it are two parts which do notpertain toan ordinary clock-train, being therefore in some sense distinctive of mypresent invention-viz., the winding-cam I and the automaticswitch,composed of an insulated collar G and an uninsulated collar G,both rigid with the sleeve E.

N is the armature for the winding-magnet N. It is secured to a lever Nfulcrumed on the frame by means of a rock-shaft n and provided at oneend remote from the fulcrum and from the armature with anantifrictionroll n adapted to bear upon the periphery of the winding-camI An arm at of the lever, projecting approximately at right angles tothe main extent of the lever from the pivot 7b to the end which has theroll a is weighted as seen at n, the weight tending to hold the armatureout of contact with the poles of the magnet and the roll 72 away fromthe shaft 0. The spur n thrown out from the back of the main arm of thelever N steps against the frame-post M and thereby limits the movementof the lever in the direction which withdraws the armature from thepoles of the magnet. An adj Listing-screw it, set through the arm whichhas the weight it, and most conveniently through said weight, projectstoward the same post M and collides against it upon the opposite sidefrom that at which the spur N is stopped and serves to stop the lever inthe direction in which it moves when the armature approaches themagnet-poles, said screw being designed to be adjusted so that thearmature shall just barely avoid contact with the magnet-poles,

contact being undesirable for reasons well understood.

The circuit-wire from one pole of. the energizing-battery runs to themagnet N and from the nutgnct to any convenient point'for binding it tothe frame,as at w. From the other pole of the battery the wire runs tothebinding-post 71, mounted .in the insulatirig-block 71 and makingpermanent contact with the switch-spring ll, which it binds rigidly tothe insulating-block. The switch-spring ll atits end remote from itsfastening to the insulating-block bears on the switching device,consisting of the collars G and G, and is thrown from one to the otherof said collars as the sleeve rotated or rocked. The construction ofthis switching device is substantially that which is shown in my PatentNo. 550,822, dated December 3, 1895, and need. not be further describedhere except by saying that the end of the swit:chspring travels on theinsulated collar while the train is running down, the track and the end.of the switchspring being so formed that the latter slips onto theuninsulated collar when the spring is run down so far as to requirewinding and runs on the latter collar during the winding process,slipping back onto the insulated collar at the limit of the windingmovement. In this part of the clock the features which ale concerned inmy present invention are the form of the winding-cam 11 and the relationof the same to the arn'iaturc and. armaturclevers and stops for thelatter.

Referring to Fig. 3, it will be seen that when. the magnet N isenergized so as to attract the arnntturc the movementofthe armaturetoward the magnet forces the upper end of the lever N in toward theshaft (1, and the roll 2/ bearing upon the periphery of the winding-caml causes such movement of the lever to rotate the shaft (t through somuch of an are as is contained between the radii which contain thepoints of contact, respectively, of the roll on the cam at the twolimits of such movement, which is designed to be about ninety degrees.The angular movement of the lever itself, which rotates the cam ninetydegrees, will be. seen in Fig. 33, being substantially the angle of olcning between the face of the armature N and the poles of the magnet N,from OOlllpflllSUll of which angles it will appear how much the movementis multiplied by the mechanical connection.

The special purpose of this inveutiou,which is at this point animprovement upon a device fora similar purpose shown in my Patent No.534,320, dated Feln-uary ll), 1805, above mentioned, is that by lm'mingand actuating the cam as herein shown I am able to make the powernecessary to be applied to the cam for each degree of rotation which itreceives in the winding movement correspond precisely with the powerdeveloped at each degree of such winding movement by the attraction ofthe magnet and armature for each other, to r it will be understood thatthe pull upon the armature caused by the attraction of the magnetincreases very rapidly as the armature, yieldingto that pull, amiroaehesthe poles ol' the magnet, and in order that this increased pull shouldbe utilized the work done through the armature-lever per degree ofmovement must increase in the same ratio as the pull of the magnet uponthe armature increases.

It will be noticed that when the armature commences to move toward themagnet, the pull being at its minimum, the leverage obtained by means ofthe cam is greatest and the amount ot pull necessary to produce a givenangular movement ol. the (mm is least. It will be noticed, also, thatthe form ol. the cam is such that this leverage diminishes rapidly asthe lever swings in toward the shaft and rotates the magnet, making thework done per degree of the armaturcs nmvemcnt. increase witheorrespoln'b ing rapidity. The law governing the increase of thelnagnets attraction for the armature being known, the Form of the cam l1computed substantially according to the same law, and thereby themaximum el'iTectivemss ot' a given current energizing the nmgnet isobtained in the winding 01' the mainspring.

The action being practically ins'lantaneous when the circuit is closed,the roll it would come to a stop at the innermost point of the cam witha blow upon the latter, and therefore upon the shaft (.1. This beingespecially undesirable, l have provided so that the lever is stoppedbefore the roll. can give-a blow to the shaft. Such stoppage might beel'lfceted by contact of the armature with .nlagnet, but for wcll-knownreasons it desirable that these parts should not come into absolutecontact. Hence I employ thesliop-screw n, which collides with thel'ranlc-post M and may be adjusted by screwing it through the levcnarmol' the armature so as to permit the utmost movement which ispermissible, and yet prevent the blow, which is u udesired. The stoppageol. the lever in the opposite direction, by means olf the spur N againstthe same post M causes the lever to stand in such position that the roll01' will be in contact with the cam at the time the circuit is closed,and will therefore begin to actuate the cam as soon as it begins tomove, not be ing obliged to travel through an interval and strike thecam, thus wasting power, before commencing to move it.

Anotherfeature of my improvement relates to the synchronizing devicesand the hand driving train. lleretolfore inv clocks lntving aseconds-hand revolving about a dill'ereut center from the minute-handone ot' two methods has been followed. lllither the seeends-hand hasbeen mounted upon a shalt of the principal train, usually theescapewheel shaft, and driven positively by such shaft, and the trainfrom the minutehand to thehour-haudhasbecnfrietiouallyconntaitet'l.

Lil

at one shaft, usually the minutehand shaft, to the principal train, sothat the minutehand and hour-hand could be set at any time regardless ofthe running of the principal train, but without the setting of thesecondshand, or the seconds-hand has also been frictionally connected toits shaft and has been driven in a train with the hour-hand andminute-hand, so that by means of the minute-hand all three of the handscould be set, the connection slipping at both points of frictionalengagementto wit, on the minute hand shaft and the seconds-hand shaft. Athird method, partaking of the elements of both those mentioned,has alsobeen employed, or, when the movement has been adapted for synchronizing,the seconds-hand is provided withfrictional connection with its shaftand the minute and hour hand train with a frictional connection at theminute-hand shaft, but the seconds-hand is not driven by thefrictiona-lly-connected train which connects the other hands. Thisconstruction requires two synchronizing connections, one to set theminute-hand, and thereby the hour-hand, and another to set theseconds-hand. This part of my invention consists in driving all thethree hands in one train, that train having a frictional connection withthe driving or principal train at an intermediate shaft in thetrain.that is to say, neither at the minutehand shaft nor at theseconds-hand shaftand a third specific feature consists in synchronizingby action upon a wheel in said frictionally -driven train intermediatethe minute-hand and the seconds-hand, preferably the wheel on the shaftat which the frictional connection is made.

Another specific feature of my invention consists in utilizing the threeshafts of the principal train as shafts of the hand-train and mountingthe entire train, from the minute-hand to the seconds-hand, on suchthree shafts and causing the several wheels in such train to operate inunison with the wheels in the principal or driving train on said shafts,respectively.

In addition to these features I have shown a specific form ofsynchronizing device which constitutes one feature of my invention,whichwill be more fully explained hereinafter.

On the shaft 1), in front of the frame, is the gear-wheel Q and pinionQ, formed rigidly as aunitary wheel, frictionally carried with theshaft 1) by means of the spring q, stopped against the shoulder b on theshaft and act-- ing against the rear disk (1 of the pinion Q, athumb-screw q, screwed into the forward end of the shaft and bearingagainst the sleeve-like extension Q of the hub of the wheel, serving toforce the wheel onto the spring, whereby the frictional engagementisobtained. The pinion Q drives the gear R, which is loose on the shaft 0,the hub of this gear being a sleeve 1, which extends forward and carriesthe minute-hand Y at its forward end. The Wheel Q meshes with the pinionS,

which is loose on the forward end of the shaft 0 and which has theforwardly-extended hub S, which carries the seconds-hand X. Thegear-wheel Q is a duplicate as to size and number of teeth of the gearB. The pinion Q is in the same respects a duplicate of the pinion B. Thegear-wheel R is likewise a duplicate of the gear-wheel A, and the pinionS is a duplicate of the pinion C. These several wheels in front of theframe therefore have, during the running of the movement, the same speedas the shafts, on which they are nevertheless mounted loosely. lViththis construction the three hands are maintained in unison after beingonce so mounted on their respective shafts, and in setting the clocks inthe customary manner, by rotating the min ute-hand, not only will thehour-hand be rotated in unison, but the seconds-hand also.

For the purpose of synchronizing*that is, setting the clock periodicallyin agreement with any controlling ohronometer with which itssynchronizing devices are electrically connectedI provide the wheel Qwith an abutment in the form of a roll Q, mounted on the stud q, theroll being greater in diameter than the tubular hub Q of the Wheel Q,and on the shaft 9, suitably supported on the frame, I mount the lever P1, whose arm P carries the armature P for the magnet P, while the arm Pextending in front of the wheel Q and past the shaft of said wheel, isadapted to strike the abutment Q. The edge or facep of the lever-arm Ptoward the abutment is straight, and its direction is substantiallyradial with respect to the shaft 29. If this face or edge 133 wereuninterrupted throughout the entire extent which could encounter theabutment, it would tend, when it encountered the abutment on the side ofthe shaft (9 toward said lever-arm at any position except in a radius ofthe shaft Z) at right angles to said edge 19 to rotate the wheel Q oneway or the other,

according to the position of said roll one side or the other of theradius at right angles to the edge. By this means the wheel Q might berotated any distance less than ninety degrees if at the instant ofsynchronizing the abutment was anywhere except at the one pointindicated on the side of the shaft 2) toward thelever-arm P If, however,the abutment happened to be anywhere in the other half of its circuit,the lever P would not act upon it and the clock would not besynchronized. In order, therefore, to adapt the leverarm P to rotate thewheel Q whichever side of the shaft the abutment may stand at theinstant of synchronizing, I make the notch 19 in the lever-arm Pinterrupting the face or edge p and adapting the lever to stride the hubof the wheel Q, so that the edge 13 at both sides of the notch mayextend past the shaft Z) when the lever is rocked, and may encounter theabutment Q and rotate the wheel Q when said abutment is on the fartherside of the shaft, as well as when it is on the proximate side. Aspecial advantage is obtained by this notch in addition to the fact thatthe lever is adapted to reach past the shaft, which may be understood byobserving that if the wheel were on the extreme end of its shaft, theshaft 10 p on theabutment should bein aline through the axis of thewheel Q at right angles to the edge p, but as the abutment approachessuch point, the angle between its direction of movement and the line ofpressure exerted by the lever approaching a right angle, it would seldomhe brought to rest exactly at the theoreticz'tl point indicziited, forif the stroke were slowit would stop short of it, and if it were rapidthe momentum of the wheel would carry the abutment beyond that point,and it would come back to it only with the slow movement due to thecontinuing pressure of the lever, so that rarely, if ever, would it restat the exact point desired. \Vhen, however, a notch is made in the edgep, the corners of the notch being at some little distance from the pointwhere the roll would be tangent to the edge p" if the latter wereuninterrupted, the roll runs off the edge into the notch some timebeforethe angle of pressure becomes disadvantageous, and the roll lodges inthe notch in contact with both its corners, this position beinginvariably attained whenever the lever is actuated. 'ltbccomesimmaterial, therefore, whether the corners of the notch areexactly equidistant from the theoretic point at which the abutment wouldrest upon the edge if the notch were not made, but the intention of thestructure preferably to make the notch symmetricz'tl with respect to theradius of the shaft 1),

which is at right angles to the edge 1) when the latter is at the limitof its forward stroke upon the abutment. .Vhen the hands are originallymounted, they will be set together at the sync]ironizing-point, saytwelve oeloek, with aroll Q :in the position on the side of the shaft t)opposite the lever l to which it would be forced by the stroke of thatlever. At such position, therefore, it should stand at the nextsynchronizing period, twelve oclock of the next day. If the movement hasbeen fast or slow to an extent less than necessary to cause the abutmentat twelve oclock to stand on the side toward thelever P and so nearly ina line at right angles with the face of the lever that the latter willnot force it back by its 3 nchronizingstroke,the stroke of the leverwill steer the abutment to the proper point opposite the shaft from thelever, thereby setting the three hands at twelve ocloek and in perfectunison. As illustrated, the lover, by its stroke upon the abutment, willrotate the latterfrom any point outside of an a re of about sixtydegrees on the side toward the lever. It is capable, therefore, ofrotating the wheel Q through one hundred and fifty degrees either way tothe synchionizing-point. As the train is constructed, one hundred andfifty degrees movement of this wheel corre sponds to three minutesrunning time of the train. The device, therefore, is :n'lapted to makeamaximum correction of three minutes either waythat is, for loss orgain.

Obviously the train may be constructed so that the correction may reachany desired amount within necessary limits.

It will be understood that the synchronizing-circuit is closed by asuitable circuit-closing device in the clock-train. This is not shown inthe drawings. Any well-known device for that purpose may be employed.

In order to facilitate the work of cleaning and repairs, I make thepinion S, which is loose on the shaft (3, as explained, so that it maybe retained on the shaft and rcz'idily rcmovable therefrom without thenecessity of extending the shaft through the long hub of the pinion,which it is necessaryto )l()\"lt li) in order that it may carry thesecondshand at its forward end. A device for this purpose is shown inFigs. l and 5. The pinionv and its hub is drilled at the center from therear side, seen at s, the shaft 0 being turned down to a size whichmakes it loose in the pinion at this point. Ata point which would beforward of the pinion when the latter is in place, and stopped at itsrear end against the shoulder c of the shaft, 1 make a peripheralannular groove c in the shaft, and at a corrcspoiuling point in the hubof the pinion S, forward of the latter, I cut through into the interioraperture of the hub at a, andon the outside of the hub at this point Iplace a spring-clasp s", whichis held in place by its ends 'elasping thehub, as seen in Fig. :7, a straightportion s of the clasp between theends lodging in the aperture s of the hub and in the annular groove ofthe shaft, and by its engagement with the shaft in said annular grooveand with the hub in said notch it retains the pinion longitudinally onthe shaft, while permitting itto rotate frcely,the straight portion s ofthe clasp traveling around in the annular groove 0 during such rotationof the pinion. A repairer will use a pin or other delicately-pointcdinstrument to spring the clasp up out of the annular groove and willthen withdraw the pinion longitudinally from the shaft when he desiresto dismantle the movel'nent for any purpose requiring the separation ofthe frontand rear plates of the frame.

I clairn- 1. In a chronometer, in combination with the winding shaft,drum or barrel, the cam thereon; the elcctromagnet and its armature, andthe lever which carries the latter ln ing an abutment adapted to operateagainst the cam; the lever having an arm ai'la-pted to he stopped bycollision with the frame in the movement caused by the attraction of themagnet for the arlnature, one of said colliding parts having anadjustmentscrew by which the collision may tend, with respect to theapproach of the armature to the magnetpoles and of the abutment to theend of the cam-track, whereby the armature may be prevented from contactwith the poles, and the abutment prevented from giving a blow to thecam: substantially as set forth.

2. In a chronometeighaving a seconds-hand rotating about a differentcenter from the minute-hand, in combination with the principal train, atrain connecting the three hands, said train having frictionalconnection only with the principal train, such connection be ing at awheel in said train intermediate be tween the minute and seconds hands.

3. In a chronometer in combination with the principaltrain, a trainconnecting the seconds-hand, min ute-hand and hen r-han d, such trainbeing connected to the principal train frictionally, and not positively,the wheels of such train which extend from the minutehand to theseconds-hand being mounted on the shafts of the principal train, andhaving the speeds of such shafts respectively, the frictional connectionbeing made at an intermediate shaft of the principal train andcorresponding intermediate wheel of the handstrain.

-il-. I11 a chronometer, in combination with the principal train, atrain frictionally connected with the principal train and connecting theseconds-hand, minute-hand and hourhand, a wheel in said trainintermediate between the seconds-hand and minute-hand, being providedwith a synchronizing device, and

an electromagnet and its armature provided with lever-arm adapted tooperate upon such synchronizing device.

5. In a chronometer, in combination with the principal train, a trainfrictionally connected with such principal train, and extending betweenthe seconds-hand, minute-hand and hour-hand, such frictional connectionbeing made at a wheel intermediate in the train between the minute-handand the secondshand, and a synchronizing-leveradapted to operate uponsuch intermediate wheel.

6. In a chronometer, in combination with the principal train having theescapementwheel staff extending forwardly through the frame; a train infront of the frame comprising a pinion mounted on theforwardly-protruding staff of the escapement-wheelg the hub of saidpinion having an aperture and the staff having an annular groove in aposition corresponding to said aperture; and a spring-clasp exterior tothe hub having a portion which lodges in the aperture and extends intothe annular groove of the shaft, whereby the pinion is longitudinallystopped on the shaft and detachably disengaging the clasp: substantiallyas set forth.

In testimony whereof I have hereunto set my hand, in the presence of twowitnesses, at

Chicago, Illinois, this 7th day of December,

CHAS. M. CROOK.

IVitnesses:

CHAS. S. BURTON, JEAN ELLIOTT.

